CN105590985B - Based on the sub- device of two-dimentional layer material p i n heterojunction photovoltaics - Google Patents

Abstract

A kind of avalanche probe based on stratified material p i n hetero-junctions, described avalanche probe are included in substrate provided with structure from bottom to top：Insulated substrate layer, the insulating barrier include the flexible insulating substrates such as silica, PMMA；P i n hetero-junctions, the p i n hetero-junctions includes p type semiconductor two-dimensional film materials, the p types semiconductor two-dimensional film material is that film layer 5 is overlayed under a larger intrinsic semiconductor of boron nitride band gap or insulating barrier for including the determination number of plies, n type semiconductor two-dimensional films material film 4 is overlayed on above-mentioned boron nitride, whole heterojunction device is placed on the insulating barrier, and boron nitride separates two semiconductor two-dimensional film material layers；Top-gated insulating barrier includes silica, alundum (Al2O3), hafnium oxide, ITO etc.；Top-gated metal electrode layer 7 is on the top-gated insulating barrier.

Description

p-i-n heterojunction optoelectronic devices based on two-dimensional layer transfer materials

technical field

The invention relates to the p-i-n heterojunction optoelectronic technology of two-dimensional layer-transfer materials, in particular to a p-i-n heterojunction-based optical avalanche single-photon detection.

Background technique

Weak photoelectron detectors have important applications in optical communication, space research and military affairs. As a highly sensitive photodetector, it can convert light signals into electrical signals, and then use it to detect the position and shape of objects. However, most of the most widely used single-photon detectors use superconducting arrays and need to work in a low-temperature environment. In particular, high-sensitivity low-light detectors have broad application requirements in the fields of cosmology research and aerospace, as well as missile guidance and quantum communication on high-end weapon platforms, which are the top priorities of research that focuses on and invests at home and abroad. , It is of great significance to develop cutting-edge science and technology and strengthen the construction of national defense core forces. At the same time, high-sensitivity single-photon detection technology also has extensive application requirements in various industries and departments such as industry, agriculture, medicine, and transportation, such as online power detection, mineral resource exploration, temperature and gas measurement in underground mines, landform or environmental monitoring, crop or Environmental monitoring, weather forecasting, etc. have made weak light detection technology develop into a dual-use technology for military and civilian use. With the continuous improvement of the performance requirements of photodetectors, traditional detectors are no longer sufficient. In this context, the emergence of two-dimensional layered materials has brought a new dawn to the field of photodetectors. Taking molybdenum sulfide as an example, this emerging two-dimensional carbon atom film shows strong light-matter interaction and strong light absorption. And because of its excellent semiconductor electrical properties and convenient microfabrication technology, heterojunction photodetectors based on two-dimensional thin film materials show great potential.

Photovoltaic detectors are ideal photodetectors. Photovoltaic devices form a p-n junction due to the contact of semiconductors of different doping types, or a Schottky barrier is formed by the contact of metal and semiconductor. The mechanism of the photoelectric response is the separation of photogenerated electron-hole pairs by the built-in electric field. However, in two-dimensional thin film materials, the p-n junction built-in electric field region with atomic layer thickness is almost at the atomic scale. At the same time, semiconductor materials have relatively large band gaps. The cut-off band for light absorption is relatively short, and the bands of traditional silicon detectors are concentrated in the visible and near-infrared bands. Other infrared detectors such as indium gallium arsenic have relatively long detection bands, and the disadvantage is that they need low temperature to work normally. These detectors have obvious limitations and disadvantages.

Contents of the invention

The object of the present invention is to provide an optoelectronic device based on layered material heterojunction, so as to reduce the volume of the detector and realize room temperature, high-sensitivity avalanche single-photon detection.

In order to achieve the above object, the technical solution of the present invention is an avalanche detector based on a layered material p-i-n heterojunction, and the avalanche detector includes a bottom-up structure on the substrate:

A substrate insulating layer, which includes flexible insulating substrates such as silicon dioxide and PMMA;

p-i-n heterojunction, the p-i-n heterojunction includes a p-type semiconductor two-dimensional thin film material (thin film layer), and the p-type semiconductor two-dimensional thin film material, that is, thin film layer 5, is stacked on a nitride layer comprising a certain number of layers Boron 3 has a large band gap under the intrinsic semiconductor or insulating layer, and the n-type semiconductor two-dimensional thin film material film 4 is stacked on the above-mentioned boron nitride 4, and the entire heterojunction device layer is placed on the insulating layer, and the nitride Boron separates the two semiconductor two-dimensional thin film material layers;

The metal electrode layer includes a source electrode layer 8 and a drain electrode layer 6. The source and drain electrode layers are respectively arranged in contact with the semiconductor layer covering the n-type two-dimensional layered thin film material and the p-type two-dimensional layered thin film material, and covered on the On each end of the thin film layer of n and p two-dimensional layered thin film materials;

A top gate insulating layer 2, the top gate insulating layer includes silicon dioxide, aluminum oxide, hafnium dioxide, ITO, etc.;

The top gate metal electrode layer 7 is on the top gate insulating layer.

In one embodiment, the thin film layer of semiconductor two-dimensional thin film material is transition metal chalcogenide, black scale and the like.

In one embodiment, the insulating layer is a silicon dioxide layer, a PMMA layer or a germanium sheet.

In one embodiment, the intermediate layer is an intrinsically layered semiconductor or an insulator with a large band gap.

In one embodiment, the insulating layer has a thickness of 300 nanometers.

In one embodiment, the top gate insulating layer is 10nm hafnium dioxide.

In one embodiment, the source electrode layer is composed of 5 nm thick palladium and 50 nm thick gold.

In one embodiment, the drain electrode layer is composed of 5 nm thick titanium and 50 nm thick gold.

In one embodiment, the top gate electrode layer is composed of 5 nm thick titanium and 50 nm thick gold.

In order to achieve the above object, an embodiment of the present invention needs to provide an avalanche photocurrent measurement system.

Described heterojunction photodetector comprises:

an insulating layer, the insulating layer is 300 nanometer silicon dioxide;

A substrate insulating layer, which includes flexible insulating substrates such as silicon dioxide and PMMA;

A top gate insulating layer, the top gate insulating layer includes silicon dioxide, aluminum oxide, hafnium dioxide, ITO, etc.;

p-type two-dimensional thin film material thin film layer, the p-type two-dimensional thin film material thin film layer is stacked on boron nitride with a certain number of layers, and the n-type two-dimensional thin film material thin film is stacked under the above-mentioned boron nitride, The entire heterojunction device layer is placed on the insulating layer, and graphene separates the two semiconductor layers;

The metal electrode layer includes a source electrode layer and a drain electrode layer, and the source and drain electrode layers are respectively arranged on the p-type two-dimensional thin film material and the n-type two-dimensional thin film material semiconductor layer, and covered on the two-dimensional thin film material On one end of the thin film layer; the top gate metal electrode layer is set on the top gate insulating layer. In an embodiment, the heterojunction detector sensor further includes: a substrate disposed under the insulating layer.

During the avalanche multiplication photocurrent test, the detector hints that a high bias voltage is applied to the device, so that the photogenerated carriers in the i layer are accelerated by a strong electric field to obtain high enough kinetic energy, and they collide with the crystal lattice Ionization generates new electron-hole pairs, and these carriers continue to cause new impact ionization, resulting in avalanche multiplication of carriers and current gain. When the reverse bias voltage is near the avalanche point, very few incident photons will produce high gain. Thus, extremely weak or even single photon detection can be realized.

The heterojunction detector of the present invention is different from traditional detectors. First of all, the detector of the present invention uses a two-dimensional thin film material layer as a photosensitive element, which is different from traditional photodetection elements, and the heterojunction detector can be made very small. Secondly, the boron nitride intermediate layer in the heterojunction of two-dimensional thin film materials can greatly reduce the dark current. In order to achieve high signal-to-noise ratio and high detection rate. The avalanche point is at a high reverse bias voltage, the dark current is very low, and a small amount of photons may obtain a high avalanche gain. At the same time, the most important thing is that the detector detects the infrared band and can work at room temperature.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a device structure diagram of a p-i-n photodetector based on a layered material according to Embodiment 1 of the present invention;

Fig. 2 is a weak light detection diagram of a p-i-n photodetector based on layered materials according to Embodiment 1 of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention. The source electrode layer and the drain electrode layer are respectively arranged on the two semiconductor layers; the top gate electrode is arranged on the top gate dielectric layer.

The p-i-n heterojunction device includes a back gate and a top gate structure, the back gate is used to adjust the carrier concentration of the bottom semiconductor; the top gate electrode is used to adjust the carrier concentration of the top semiconductor material. The p-i-n heterojunction photodetector and related field-effect electronic devices of the present invention can form a p-i-n junction with atomic thickness. Compared with traditional photodetectors, the dark current is smaller, the volume is smaller, and the specific detection efficiency is very high. The avalanche effect provides a device basis for the detection of extremely weak light or even single photon.

As shown in Figure 1, the embodiment of the present invention provides a p-i-n photodetector based on a layered material heterojunction, and the heterojunction photodetector includes: insulating layers 1, 2, metal electrode layers 6, 7, 8 and two-dimensional film material film layers 3, 4, 5 and base layer 9.

3, 4, 5 stacked heterojunctions are placed on the insulating layer 1. The source electrode 8 and the drain electrode 6 are respectively arranged on the n-type two-dimensional film material film layer 4 and the p-type two-dimensional film material film layer 5, and the high dielectric insulating layer 2 covers the above-mentioned heterojunction. The top gate electrode 7 is made on the heterojunction covered by the dielectric layer 2 .

In one embodiment, the source electrode layer is composed of 5 nm thick titanium and 50 nm thick gold, and the drain electrode layer is composed of 5 nm thick palladium and 50 nm thick gold.

The p-i-n heterojunction detector also includes: a base 9, which is arranged under the insulating layer 1. The base 9 can be an insulating material such as silicon, and the present invention only uses silicon as an example for illustration.

The two-dimensional thin film heterojunction layers 3, 4 and 5 are the core part of the heterojunction p-i-n detector of the present invention, and the middle layer of boron nitride can reduce dark current and increase the width of this region. When the device is near the high reverse bias avalanche point, extremely weak photon incidence can obtain higher avalanche gain. This enables the device to obtain a high signal-to-noise ratio and realize highly sensitive light detection and even single-photon detection.

The semiconductor two-dimensional film material film layer in the heterojunction p-i-n detector of the present invention can be doped graphene film, transition metal chalcogenide, black scale, black arsenic phosphorus and the like. The intermediate semiconductor layer can also be a transition metal sulfide, oxide or boron nitride with a large band gap. The present invention only refers to the boron nitride thin film, and is not intended to be limited.

The insulating layer 9 of the p-i-n heterojunction of the present invention can be an insulating material and a high dielectric material. The insulating material is, for example, a silicon dioxide layer, a PMMA layer and a germanium sheet. The present invention only uses the silicon dioxide layer as the insulating layer for illustration.

The insulating layer 2 in the pressure sensor of the present invention can be an insulating material and a high dielectric material. The insulating material is, for example, a silicon dioxide layer, aluminum oxide, tantalum pentoxide, etc., and the present invention only uses the hafnium dioxide layer as the insulating layer. Be explained.

In one embodiment, the thickness of the insulating layer 2 is 10 nanometers, and the present invention is not limited thereto.

The fabrication process of the p-i-n heterojunction detector will be briefly introduced below with specific examples.

The manufacturing process of the p-i-n heterojunction is as follows: For the case where the silicon dioxide layer is used as the insulating layer and silicon is used as the substrate, the silicon dioxide layer and the silicon substrate are collectively called a silicon oxide wafer. During specific fabrication, a silicon oxide wafer is taken, the silicon oxide wafer is below a silicon layer, and above it is a 300nm silicon dioxide layer. Boron nitride and semiconductor thin film materials are cleaved on the surface of silicon oxide wafer. The prepared target sample is stacked on the n-type semiconductor layer on the boron nitride using the van der Waals heterojunction transfer method, and then the sample combined with the n-type semiconductor layer and boron nitride is stacked on the target p-type Thin layer of semiconductor. In this way, the p-i-n heterojunction is transferred on the above-mentioned 300nm silicon oxide silicon wafer. The source electrode and the drain electrode are respectively made by electron beam exposure or photolithography. Then ALD or magnetron sputtering is used to make the top gate dielectric layer. In one embodiment, 10 nanometer hafnium dioxide is deposited by atomic layer deposition. Then the top grid electrode is made by electron beam exposure method. This completes the fabrication of the device.

The method of obtaining boron nitride film:

1) Mechanical peeling method: mechanically peel off the boron nitride film on the processed silicon oxide wafer, and find the boron nitride film with the target thickness under the optical microscope.

2) CVD growth method: Graphene film crystals grown by CVD are then transferred to silicon oxide wafers. Or method of semiconducting thin film:

1) Mechanical exfoliation method: mechanically exfoliate the transition metal sulfide film on the processed silicon oxide wafer, and find the sample thin film crystals with thin layers under the optical microscope.

2) CVD growth method: the semiconductor thin film crystal is grown by CVD, and then transferred to the silicon oxide substrate.

Make the metal electrode layer by mask method evaporation: find the p-i-n heterojunction at a specific position, align the heterojunction with the pre-made mask, put the silicon oxide wafer together with the mask into the electron beam evaporation In the system, 5nm-thick titanium and 50nm-thick gold are evaporated and deposited in an electron beam evaporation system, and the metal source electrode layer is deposited, and 5nm-thick palladium and 50nm-thick gold are deposited, and the metal drain electrode layer is deposited. The top gate electrode layer was evaporated to a thickness of 5 nm of titanium and 50 nm of gold.

The weak light avalanche detection system is shown in FIG. 2 , and an embodiment of the present invention provides an avalanche light detection system. The avalanche light detection system consists of a current amplifier 10 , a current data acquisition 11 , a current and voltage source 12 and a laser light source 13 .

Corresponding descriptions are omitted.

The p-i-n heterojunction detector of the present invention is different from traditional photodetectors. First of all, the sensor of the present invention uses a two-dimensional thin film material layer as a photosensitive unit, which is different from the traditional photodetection unit, and the p-i-n heterojunction detector can be made very small. Secondly, the built-in electric field of the heterojunction of the two-dimensional thin film material layer is different from the traditional macroscopic heterojunction, and the depletion region is very small. The light absorption of two-dimensional thin film materials is strong, which is completely different from the light absorption of bulk materials. Finally, the existence of boron nitride in the heterojunction of two-dimensional thin film materials can make the dark current very small, high avalanche gain under high reverse bias voltage, and can realize weak light detection or even single photon detection. And it can realize weak light detection. This makes it possible to apply the p-i-n heterojunction photodetector of the present invention to applications that require high-sensitivity photodetection and single-photon detection at room temperature.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow diagram procedure or procedures and/or block diagram procedures or blocks.

In the present invention, specific examples have been applied to explain the principles and implementation methods of the present invention, and the descriptions of the above examples are only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to this The idea of the invention will have changes in the specific implementation and scope of application. To sum up, the contents of this specification should not be construed as limiting the present invention.

Claims (4)

1. An avalanche detector based on layered material p-i-n heterojunction, characterized in that, said avalanche detector comprises a bottom-to-top structure on the substrate: Substrate insulating layer, described insulating layer comprises silicon dioxide, PMMA flexible insulating substrate; p-i-n heterojunction, the p-i-n heterojunction includes p-type semiconductor two-dimensional thin film material, the p-type semiconductor two-dimensional thin film material is stacked under a boron nitride including a certain number of layers, n-type semiconductor two-dimensional thin film material The two-dimensional thin film material film is stacked on the above-mentioned boron nitride, the entire heterojunction device layer is placed on the substrate insulating layer, and the boron nitride separates the two semiconductor two-dimensional thin film material layers; the top gate metal electrode is made on the top gate On a heterojunction covered by a dielectric layer; The metal electrode layer includes a source electrode layer and a drain electrode layer, and the source electrode layer and the drain electrode layer cover the n-type two-dimensional layered film material and the p-type two-dimensional layered film material semiconductor layer respectively, and cover the n-type two-dimensional layered film material semiconductor layer. and p two-dimensional layered thin film material at one end of the thin film layer; the top gate metal electrode layer is on the top gate dielectric layer, that is, the top gate insulating layer, and the top gate insulating layer includes silicon dioxide, aluminum oxide, di Hafnium oxide or ITO; the thickness of the top gate insulating layer is 10-30 nanometers; The p-type semiconductor two-dimensional thin film material and n-type semiconductor two-dimensional thin film material include black scale, transition metal chalcogenide or graphene. 2 . The p-i-n heterojunction avalanche detector according to claim 1 , wherein the thickness of the top gate metal electrode is 20-50 nanometers. 3 . The p-i-n heterojunction avalanche detector according to claim 1 , wherein the source electrode layer is composed of titanium with a thickness of 5 nm and gold with a thickness of 50 nm. 4 . The p-i-n heterojunction avalanche detector according to claim 1 , wherein the drain electrode layer is composed of titanium with a thickness of 5 nm and gold with a thickness of 50 nm.